• 한국수학교육학회지시리즈C:초등수학교육
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• 제6권1호
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• pp.1-10
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• 2002

The objectives of the current study are on the practical use of geoboard in an elementary school class. To do this, we first investigate how come geoboard is significant in a practical use. Second, we present an example of practical use of geoboard connecting with the analysis of the 7th curriculum. Third, we investigate the results of geoboard which is applied to elementary school class. The results of this research are as follows: First, the instruction of using geoboard can give an interest and curiosity to all students. Second, right triangle, rectangle, square and so on can be easily constructed because geoboard is linked by dots. Third, by constructing figures on geoboard and comparing figures which is made by themselves, students could better understand the concept of figures rather than the explanation of teacher. fourth, students can be improved the ability of problem solving and spatial sense by providing experience for exploration. Fifth, students need not to have anxiety for error because geoband is used and so can be corrected easily.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.132-139
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• 2000

This paper presents a new hybrid approach for nonlinear dynamic analysis of the soil-structure interaction system in the time domain. It employs, in a practical manner, a linear SSI program and a general-purpose nonlinear finite element program. In order to demonstrate the validity and applicability of the proposed method, seismic response analyses are carried out for a free-field problem and a 2-D subway station. The results indicate that the proposed methodology gives reasonable solution for the linear/nonlinear SSI problem utilizing a general-purpose finite element program. Some further studies will endorse the applicability of the method to various soil-structure interaction problems.

• 산업공학
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• 제22권1호
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• pp.38-43
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• 2009

This paper deals with two most important problems, from both practical and theoretical standpoints, arising when building the ships in N different docks. Such docks have become core components of modern ship construction. One problem is to minimize the number of building docks in the shipyard, while the other is to keep the usage rate of resources fed into docks as constant as possible. In this paper the combined problem is formulated as a single-integer programming model. The LP-relaxation of this model is solved by column-generation techniques. Practical applications of this formulation are also discussed.

• Journal of Electrical Engineering and Technology
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• 제4권3호
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• pp.337-345
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• 2009

Deregulation in power industry has made the reactive power ancillary service management a critical task to power system operators from both technical and economic perspectives. Reactive power management in power systems is a complex combinatorial optimization problem involving nonlinear functions with multiple local minima and nonlinear constraints. This paper proposes a practical market-based reactive power ancillary service management scheme to tackle the challenge. In this paper a new model for voltage security and reactive power management is presented. The proposed model minimizes reactive support cost as an economic aspect and insures the voltage security as a technical constraint. For modeling validation study, two optimization algorithm, a genetic algorithm (GA) and particle swarm optimization (PSO) method are used to solve the problem of optimum allocation of reactive power in power systems under open market environment and the results are compared. As a case study, the IEEE-30 bus power system is used. Results show that the algorithm is well competent for optimal allocation of reactive power under practical constraints and price based conditions.

• 대한산업공학회지
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• 제27권1호
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• pp.54-60
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• 2001

In this paper, a shape-based block layout (SBL) approach is presented to solve the facility layout problem with unequal-area and fixed shapes. The SBL approach employs hybrid genetic algorithm (Hybrid-GA) to find a good solution and the concept of bay structure is used. In the typical facility layout problem with unequal area and fixed shapes, the given geometric constraints of unequal-area and fixed shapes are mostly approximated to original shape by aspect ratio. Thus, the layout results require extensive manual revision to create practical layouts and it produces irregular building shapes and too much unusable spaces. Experimental results show that a SBL model is able to produce better solution and to create more practical layouts than those of existing approaches.

• 전기의세계
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• 제22권4호
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• pp.17-24
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• 1973

In the view point of practical engineering the identification problem may be considered as a problem to determine the optimal model in the sense of minimizing a given criterion function using the input-output records of the plant. In the system identification the statistical approach has been known to be very effective when the topological structure of the system and the statistical characteristics of the observation noises are known a priori. But in the practical situation there are many cases when the inforhation about the observation noises or the system noises are not available a priori. Here, the authors propose a new identification method which can be used effectively even in the cases when the variances of observation noises are unknown a priori. In the method, the identification of unknown parameters of a linear diserete system is achieved by minimizing the improved quadratic criterion function which is composed of the term of square equation errors and the term to eliminate the affection of observation noises. The method also gives the estimate of noise variance. Numerical computations for several examples show that the proposed procedure gives satisfactory results even when the short time observation data are provided.

• 한국통신학회논문지
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• 제34권3B호
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• pp.225-234
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• 2009

Recently IPTV service is penetrating to the ordinary home users very swiftly. One of the first phase of IPTV service is considered to be VoD, and a nationwide availability of the VoD service imposes tremendous pressure to the network resource due to its requirements for the broad bandwidth, the inherent nature of unicast technology, and the large scalability, etc. This work suggests a novel and practical method to the design of network resource for the VoD service. Especially, we explore the distributed content storage problem that takes into account the popularity of the video contents and its corresponding link dimensioning problem that takes into account the grade of service for the flow level quality of service about the VoD service. By assuming a realistic topology for the nationwide IP backbone network of Korea, which is a typical tree topology, we suggest an analytic method for the design of VoD service.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2004년도 추계학술대회 및 정기총회
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• pp.245-249
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• 2004

This paper deals with two most important problems, from both practical and theoretical standpoints, arising when building the ships in docks. Such docks have become core components of modern ship construction. One problem is to minimize the number of building docks in the shipyard, while the other is to keep the usage rate of resources fed into dock as constant as possible. In this paper the combined problem is formulated as a single-integer programming model. The LP-relaxation of this model is solved by column-generation techniques. The results of an experimental evaluation show that the lower bounds are tight. Practical applications of this formulation are also discussed.

• 한국건설관리학회논문집
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• 제14권3호
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• pp.157-166
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• 2013

BTL(Build-Transfer-Lease) 사업의 목적은 종래 BTO(Build-Transfer-Operate) 방식과는 달리 학교, 사회복지시설 등 최종 이용자로부터 이용료를 부과할 수 없는 공공시설에 대하여 민간자금을 유치함으로써 정부의 재정부족을 해결하고 사회기반시설의 조기 확충을 위한 방안으로 도입되었다. 하지만 BTL 사업은 그 진행과정에서 다양한 문제점을 발생시키고 있으며, 이를 개선할 수 있는 실질적인 접근이 요구된다. 이에 본 연구에서는 국내의 BTL사업의 문제점에 대한 연구 자료와 국내보다 앞서 BTL 사업을 활용하고 있는 국외 자료를 분석하여 문제 영역을 도출하였다. 그리고 이를 체계적으로 관리하기 위해 친화도 기법, 매트릭스 비교분석, AHP 기법을 활용하여 중요도를 분석하였다. 분석된 결과는 BTL 사업의 실질적 문제 영역 및 중요도 제시를 통하여 관리 기준을 제공할 것으로 기대된다.

• 한국산학기술학회논문지
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• 제15권10호
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• pp.6176-6186
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• 2014

본 연구는 간호학생의 간호 수기술 향상을 위해 사전 동영상 학습방법을 활용한 기본간호학 실습 교육평가방법의 학습동기, 학업적 자기효능감 및 문제해결과정을 파악하고자 하는 상관성 조사연구였다. 학습동기와 학업적 자기효능감은 간호과 선택동기, 전공만족도, 기본간호학실습 만족도, 사전 동영상 시청의 도움정도, 체크리스트 활용 실기평가의 적절성에 따라 통계적으로 차이가 있었다. 문제해결과정은 전공만족도, 기본간호학실습만족도, 사전 동영상 시청의 도움 정도, 체크리스트 활용 실기평가의 적절성에 따라 통계적으로 차이가 있었다. 학습동기는 학업적 자기효능감 및 문제해결과정과, 학업적 자기효능감은 문제해결과정과 유의한 정적상관관계를 나타냈다. 결론적으로, 사전 동영상 학습방법을 활용한 기본간호학실습 교육평가방법은 간호학생의 학습동기, 학업적 자기효능감 및 문제해결과정과 관련이 있었다.